1. Field of the Invention
This invention relates generally to current control circuits, and more particularly concerns a control circuit for controlling the switching of voltages applied to an inductor to establish a desired current flow through the inductor.
2. Background Art
In various types of electronic circuits, voltages are applied to an inductor in order to produce desired forms of current flow through the inductor. For example, sawtooth scan currents are produced in yoke inductors in television circuits. As another example, inductor currents are varied for transferring energy from the input to the output of off-line switching power converters.
As a more specific example, in a particular type of DC-to-DC buck converter, to be described in more detail hereinafter, the peak-to-peak current through an inductor in the buck converter is controlled to be maintained at a constant value by a control circuit. In this exemplary buck converter, the converter serves as a regulator and must be controlled to provide a regulated output voltage. The control circuit turns both the series and the flywheel FET's in this particular buck regulator on and off in a manner to maintain the peak-to-peak inductor current constant for variations in input voltage and load, with the average DC value of this constant peak-to-peak inductor current being varied by the control circuit to provide output voltage regulation.